124 



This effort may be used to replenish stock reduced by natural or artifi- 

 cial changes in the environment, overfishing or other factors, or to 

 introduce new species into an environment. Such methods are being 

 used to maintain salmon and trout fisheries and to provide sportfish 

 in areas of heavy fishing pressure. 



(4) Transplanting wild stocks as eggs, young, or spawning adults 

 from one natural area to another to provide more suitable habitat 

 for spawning, growth, or survival, and to introduce species into new 

 environments. This method has been the backbone of present day 

 oyster culture on leased grounds. This method was also used to intro- 

 duce striped bass and shad from the east coast to west coast waters. 

 Widespread transplants of salmon have also been made with varying 

 success. 



(5) A variety of other techniques have been developed to increase 

 abundance and survival of commercially valuable species, e.g., cultch- 

 ing oyster beds with shell to increase setting ; suspending shell strings 

 from floats or piling to catch larval oysters and grow the adults using 

 the total water column (fig. IV.2.11) ; moving oysters to predator or 

 disease-free areas; construction of artificial reefs to provide more 

 suitable habitat for oysters, lobsters, and fish (fig. IV.2.12) ; and 

 opening or closing breaches in barrier islands to improve environ- 

 mental conditions of essential lagoons. 



(6) Aquaculture is also practiced in the experimental rearing of 

 larval fish and shellfish to study the importance of environmental 

 factors on survival and to determine causes of the marked variation 

 in year-class size. 



Aquaculture, with a few minor exceptions, appears to be today 

 where agriculture was 50 or more years ago. True farming of the sea 

 is still in its infancy. At the present time almost all of the oysters pro- 

 duced on the west coast of the United States have at least one manipu- 

 lation by man before they are harvested; on the Atlantic seaboard 

 approximately 50 percent are manipulated at least once before harvest. 

 Other than oysters, there are no known enterprises in marine aqua- 

 culture that are expecting a significant profit. Many ventures are 

 presently underway to develop pilot plants for commercial farming 

 in the future. 



Table IV.2.2 lists the range of species that are presently being 

 studied for marine aquaculture. Research is at private, university, 

 State government, and Federal Government laboratories. 



Table IV.2.2. — Species under marine aquaculture research 



Organism : state 



Algae Florida. 



Shrimp Alabama, Florida, Texas, Louisiana, 



South Carolina, Oalifornia. 



Orabs Oalifornia, Maryland, Oregon. 



Lobsters Maine, Florida, California, Massachu- 

 setts. 



Crayfish Louisiana. 



Freshwater Shrimp Florida, Alabama, Hawaii. 



Mussel California, Oregon. 



